Simulation and modeling of wind farms in baroclinic atmospheric boundary layers

The performance of wind farms strongly depends on the prevailing atmospheric conditions. We investigated how baroclinicity, caused by horizontal temperature gradients in the atmosphere, affects wind farm performance and wake recovery, using large eddy simulations. Baroclinicity impacts the power generation in the entrance region of a wind farm by modifying atmospheric conditions around turbine height, such as the turbulence intensity. The power production of downstream turbines is also affected by baroclinicity, as it alters the kinetic energy available for entrainment above the wind farm. Furthermore, our findings reveal that the recovery of wind farm wakes is governed by wake expansion, controlled by atmospheric turbulence intensity, and by an upward shift of the wake velocity deficit, which is driven by vertical velocity shear. These insights have been incorporated into a novel engineering model designed to predict large-scale wake recovery behind wind farms in both barotropic and baroclinic conditions.